While balusters or spindles for deck and porch railings continue to be made of wood, the use of synthetic resins has many advantages, such as a reduction in or elimination of the necessity for painting or otherwise coating, good weatherability, excellent wear, good appearance, versatility of design, and inexpensive production. Wood may crack over time, frequently is chemically treated to prevent microbial and insect infestation, and can require frequent protective coatings. Combinations of angular and round surfaces are rare because the round parts must be individually turned on a lathe. In addition, wood naturally comes with inevitable imperfections such as knots and grain separation.
One of the negative aspects of using synthetic resins has been the more or less arbitrary prohibition and/or regulation of synthetic resin spindles on the theory that small children can distort them, sometimes pinching themselves between the spindles or otherwise injuring themselves. Although synthetic resins have wide ranges of tensile strength, impact resistance, stiffness and other relevant properties, regulatory agencies and sometimes the customers themselves may simply ignore the differences and assume that "plastic" is inferior. Accordingly there is a need for a synthetic resin spindle which is manifestly rigid.
Ease and particularly versatility of assembly are other attributes sought for spindles for railings. It would be desirable, for example, to be able to make railings of some variation in height using a spindle of a standard design.
It is known to encase a reinforcing member within a synthetic resin body. See, for example, Lemelson U.S. Pat. No. 4,043,721.
In U.S. Pat. No. 3,200,554, Goodman et al encase a metal tube in wood (saying plastic may be used also) to make a lamp pole. The encasement is accomplished by fabrication, however, not in a mold as in the present invention.
Bajorek et al, in U.S. Pat. Nos. 4,035,978 and 4,038,802, also fabricate covers for bars, spindles, or balusters. The covers have two sections having mating surfaces, in one case longitudinal and in the other sectional. Such a construction does not intimately embed the reinforcing rod or tube as does applicant's.
In Design Pat. No. 315,415, Anthony illustrates a "decorative vertical support" having a profile with a round central portion and two square end portions. This may be of interest to the reader because applicant's preferred end portions are also substantially square, but they are separate sleeves designed to pass over the ends of the reinforced portion.